package com.itheima.controller;

import com.alibaba.fastjson.util.IOUtils;
import com.itheima.common.R;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.UUID;

@Slf4j
@RestController
@RequestMapping("/common")
public class CommonController {
    @Value("${reggie.path}")
    private String basePath;

    //文件上传 @param File
    @PostMapping("/upload")
    public R<String> upload(MultipartFile file){
        log.info(file.toString());

        //原始文件名
        String originalFilename = file.getOriginalFilename();
        String substring = originalFilename.substring(originalFilename.lastIndexOf("."));

        //通过UUID重新生成文件名,预防因文件名重复造成文件覆盖
        String s = UUID.randomUUID().toString() + substring;

        //构建目录对象并判断其是否存在
        File f = new File(basePath);
        if (! f.exists() ){
            //不存在需创建
            f.mkdirs();
        }
        try {
            //将临时文件转存到指定位置
            file.transferTo(new File(basePath + s));
        } catch (IOException e) {
            e.printStackTrace();
        }

        return R.success(s);
    }

    //文件下载 @param name ; @param response
    /*逻辑：
    1 定义输入流，通过输入流读取文件内容
    2 通过response对象，获取到输出流
    3 通过response对象设置响应数据格式(image/jpeg)
    4 通过输入流读取文件数据，然后通过上述的输出流写回浏览器
    5 关闭资源
    */
    @GetMapping("/download")
    public void download(String name , HttpServletResponse response){
        try {
            //通过输入流读取文件内容
            FileInputStream inputStream = new FileInputStream(new File(basePath + name));

            //通过输出流将文件写入浏览器
            ServletOutputStream outputStream = response.getOutputStream();

            response.setContentType("image/jpeg");

            int len = 0;
            byte[] bytes = new byte[1024];
            while ((len = inputStream.read(bytes)) != -1){
                outputStream.write(bytes,0,len);
                outputStream.flush();
            }

            //关闭资源
            outputStream.close();
            inputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}
